micahpearlman/Predicated SIMD (NEON)

## Predicated SIMD (NEON)
Predicated execution on the NEON isn't too hard to get around. As in the code i posted you can translate:

if (cond) x = x1
else x = x0

To:

dx = x1 - x0;
x = x0;
x = x + (cond > 0) * dx;

Which is probably 2-3 cycles, the mov and sub can be issued in parallel. The problem is large branches where both paths are long and independent, you'll either have to; calculate both paths, send the flags from NEON to ARM, or calculate the conditions on the ARM. Each of these have positives and negatives. The last is best if you can precalculate the condition.
	Predicated execution on the NEON isn't too hard to get around. As in the code i posted you can translate:

	if (cond) x = x1
	else x = x0

	To:

	dx = x1 - x0;
	x = x0;
	x = x + (cond > 0) * dx;

	Which is probably 2-3 cycles, the mov and sub can be issued in parallel. The problem is large branches where both paths are long and independent, you'll either have to; calculate both paths, send the flags from NEON to ARM, or calculate the conditions on the ARM. Each of these have positives and negatives. The last is best if you can precalculate the condition.